1. Field of the Invention
This invention relates to an editing system and control method thereof and, more particularly, is suitably applied to an on-air system which is used in a television broadcasting station, for example.
2. Description of the Related Art
With an editing device which is used in an on-air system, we can create an edit list specifying edit details describing which clip and which clip are to be connected to create edited video and audio while visually confirming the video of desired video/audio material (hereinafter, referred to as clip). Then by editing and processing the video/audio data of specified clips based on the created edit list, edited video/audio based on the edit list can be created (for example, Japanese Patent Application Laid-Open No. 11-66816).
Generally, we create an edit list by processing and editing high-resolution video/audio data, which is used for broadcasting, with an editing device while confirming the obtained edited video and audio.
At this time, the editing device reads required video/audio data from an Audio/Video (AV) server of a large capacity storing various clips obtained by coverage and then processes and edits the data based on the edit list.
However, it takes a long time to read and transfer video/audio data from the AV server to the editing device because of a large amount of the high-resolution video/audio data. Therefore, we have to wait for display or output of edited video and audio after entering a playback command of the edited video and audio to the editing device, resulting in decreasing efficiency of editing work.
As a technique offered by the applicant of this invention to solve this problem, a buffer of a large capacity comprising, for example, a semiconductor memory is provided between an editing device and an AV server. In creating an edit list, required video/audio data is automatically read and stored from the AV server into the buffer according to the progress of the creation work of the edit list. And in response to a playback command of edited video and audio, the video/audio data being stored in the buffer is edited and processed based on the edit list, thereby displaying and outputting the edited video and audio immediately.
Even with this technique, however, in a case where an editing device continues the creation work of an edit list created by another editing device, video/audio data required for obtaining edited video and audio based on the edit list is not stored in a buffer. Therefore, this technique has a similar problem to the conventional case where the editing device needs a long time to take in the required video/audio data from the AV server via the buffer when displaying and outputting the edited video and audio based on the edit list.